I' working under Windows and not have another possibility (Linux, Ubuntu, Mac) because of interested me program Thermocal that installed on Windows in my office.

I wrote the python script which creates the (1) file and then I want (2) to open via python script the program Thermocal and then (3) Thermocalc must open already created file by python script and execute it. I'm blocked with step 3. Python has the command line. Thermocal has own command line. I don't have the terminal. Once I open Thermocalc via Python (throught run option) I want also via python script to write down in Thermocal command line the command 'micro-file-open'. Is it possible?

I' working under Windows and not have another possibility (Linux, Ubuntu, Mac) because of interested me program Thermocal that installed on Windows in my office.

I wrote the python script which creates the (1) file and then I want (2) to open via python script the program Thermocal and then (3) Thermocalc must open already created file by python script and execute it. I'm blocked with step 3. Python has the command line. Thermocal has own command line. I don't have the terminal. Once I open Thermocalc via Python (throught run option) I want also via python script to write down in Thermocal command line the command 'micro-file-open'. Is it possible?

wow, no offense, this sounds like a mix of not enough information and gibberish. State clearly what you are asking for, and the problem you are running into.

I too, can hardly tell what you are trying to say. I imagine however that your solution is likely using the subprocess module to execute your Thermocal script with appropriate arguments; collect the result; and save it to a file. This is a fairly blind guess though.